Cytochrome b6f - Orchestrator of photosynthetic electron transfer

Biochim Biophys Acta Bioenerg. 2021 May 1;1862(5):148380. doi: 10.1016/j.bbabio.2021.148380. Epub 2021 Jan 16.

Abstract

Cytochrome b6f (cytb6f) lies at the heart of the light-dependent reactions of oxygenic photosynthesis, where it serves as a link between photosystem II (PSII) and photosystem I (PSI) through the oxidation and reduction of the electron carriers plastoquinol (PQH2) and plastocyanin (Pc). A mechanism of electron bifurcation, known as the Q-cycle, couples electron transfer to the generation of a transmembrane proton gradient for ATP synthesis. Cytb6f catalyses the rate-limiting step in linear electron transfer (LET), is pivotal for cyclic electron transfer (CET) and plays a key role as a redox-sensing hub involved in the regulation of light-harvesting, electron transfer and photosynthetic gene expression. Together, these characteristics make cytb6f a judicious target for genetic manipulation to enhance photosynthetic yield, a strategy which already shows promise. In this review we will outline the structure and function of cytb6f with a particular focus on new insights provided by the recent high-resolution map of the complex from Spinach.

Keywords: Cyclic electron transfer; Cytochrome b(6)f; Linear electron transfer; Photosynthesis; Q-cycle; Redox regulation; Transmembrane signalling.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Cell Respiration*
  • Cytochrome b6f Complex / metabolism*
  • Electron Transport
  • Electrons*
  • Photosynthesis*

Substances

  • Cytochrome b6f Complex